Feather boards have been used for decades to hold a work piece against a guide surface, as the work piece was guided in a feed direction to a cutting tool. Such feather boards traditionally have a series of fingers extending from one edge thereof, positioned adjacent to the guide surface but spaced a clearance distance therefrom, so that the work piece may be fed between the fingers of the feather board and the guide surface. The feather board is initially positioned closely enough to the guide surface, and the fingers of the feather board are typically designed to extend at an angle to the guide surface, in such a manner that as the work piece is fed through the clearance between the feather board and the guide, the fingers are deflected slightly and exert a sideways pressure to hold the work piece against the guide. The fingers are typically attached to a body of the feather board at a point closer to the infeed end of the guide surface, with the remainder of the fingers extending at an angle in the feed direction and terminating at a plurality of distal ends which in combination define a contact surface of the feather board. Because the fingers are angled in this fashion, should the cutting tool catch the work piece and try to kick it backward toward the infeed end of the guide surface, the fingers of the feather board will be energized into the surface of the work piece and preclude the kick-back of the work piece that would otherwise occur.
Although there have been many prior attempts to designing feather boards, additional improvement is still desirable in a number of areas. For example, a common problem encountered while using feather boards is that, if the feather board is not very precisely positioned, with respect to the guide surface, the pushing force required to feed the work piece along the guide surface, against the friction generated by contact of the work piece with the distal ends of the fingers on the feather board becomes so great, part way through the operation of feeding the work piece past the cutting tool, that the work piece cannot be moved further. It would be desirable, therefore, to provide a feather board apparatus and method allowing the clamping force exerted by the feather board to self-adjust, to a limited extent, as the work piece is fed past the feather board, so that the force required to continue feeding the work piece never becomes excessive. Such a solution would be preferable as compared to other potential solutions involving very accurate measurements being required in the placement of the feather board with respect to the guide surface.
Another area in which improvement is desirable in the art of the configuration and use of feather boards, is to provide a convenience apparatus and method for utilizing feather boards for guiding and preventing kick-back with work pieces that are fairly tall, in situations, for example, such as cutting a rabbet groove along the side of a bookcase or other tall piece of furniture.
Where feather boards, or other types of attachments or adjustments on tools must be made, prior experience has shown that adjustment or locking knobs, of conventional construction, are often difficult to loosen once they have been tightened. It would be desirable, therefore, to provide an improved knob configuration which would preferentially be more difficult to tighten than to loosen, to preclude the problem of having the knob which was originally tightened by hand be too tight to be loosened by hand.
What is needed, therefore, is an improved feather board apparatus and method, addressing one or more of the problems described above, and/or other problems encountered in the use of prior feather board arrangements as are well know to those having skill in the art.